LOD_NdQSDecimator.cpp

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
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 */

#include "LOD_NdQSDecimator.h"

#include "LOD_ExternBufferEditor.h"
#include "LOD_ExternNormalEditor.h"
#include "LOD_ExternVColorEditor.h"
#include "TNT/lu.h"

#include <iostream>

using namespace std;

    LOD_NdQSDecimator *
LOD_NdQSDecimator::
New(
    LOD_ManMesh2 &mesh,
    LOD_ExternNormalEditor &face_editor,
    LOD_ExternVColorEditor &color_editor,
    LOD_ExternBufferEditor &extern_editor
){

    NanPtr<LOD_NdQSDecimator> output 
        = new LOD_NdQSDecimator(mesh,face_editor,color_editor,extern_editor);

    NanPtr<LOD_EdgeCollapser > collapser(LOD_EdgeCollapser::New());
    NanPtr<LOD_NdQuadricEditor> q_editor(LOD_NdQuadricEditor::New(mesh));

    if (
        output == NULL ||
        collapser == NULL ||
        q_editor == NULL 
    ) {
        return NULL;
    }
    output->m_collapser = collapser.Release();
    output->m_quadric_editor = q_editor.Release();
    return output.Release();
}   



    bool
LOD_NdQSDecimator::
Arm(
){
    MT_assert(!m_is_armed);
    bool heap_result = BuildHeap();
    if (!heap_result) {
        return false;
    }
    m_is_armed = true;
    return true;
}
    
    bool
LOD_NdQSDecimator::
Step(
){
    return CollapseEdge();
}


LOD_NdQSDecimator::
LOD_NdQSDecimator(
    LOD_ManMesh2 &mesh,
    LOD_ExternNormalEditor &face_editor,
    LOD_ExternVColorEditor &color_editor,
    LOD_ExternBufferEditor &extern_editor
) :
    m_mesh(mesh),
    m_face_editor(face_editor),
    m_color_editor(color_editor),
    m_extern_editor(extern_editor),
    m_is_armed (false)
{   
    m_deg_edges.reserve(32);
    m_deg_faces.reserve(32);
    m_deg_vertices.reserve(32);
    m_update_faces.reserve(32);
    m_new_edges.reserve(32);
    m_update_vertices.reserve(32);
};

    bool
LOD_NdQSDecimator::
CollapseEdge(
){
    
    // find an edge to collapse
    
    // FIXME force an edge collapse
    // or return false

    vector<LOD_Edge> & edges = m_mesh.EdgeSet();
    vector<LOD_Vertex> & verts = m_mesh.VertexSet();
    vector<LOD_NdQuadric> & quadrics = m_quadric_editor->Quadrics();
    int size = edges.size();

    if (size == 0) return false;

    const int heap_top = m_heap->Top();

    if (heap_top == -1 || edges[heap_top].HeapKey() <= -MT_INFINITY) {
        return false;
    }
    
    // compute the target position

    TNT::Vector<MT_Scalar> new_vector(6,MT_Scalar(0)); 

    m_quadric_editor->TargetVertex(edges[heap_top],new_vector,m_color_editor);


    MT_Vector3 new_vertex(
        new_vector[0],
        new_vector[1],
        new_vector[2]
    );
    for (int i = 3; i < 6;i++) {
        if (new_vector[i] > MT_Scalar(1)) {
            new_vector[i] = MT_Scalar(1);
        } else 
        if (new_vector[i] < MT_Scalar(0)) {
            new_vector[i] = MT_Scalar(0);
        }
    }
    MT_Vector3 new_color(
        new_vector[3],
        new_vector[4],
        new_vector[5]
    );

    // bounds check?

        
    LOD_NdQuadric & q0 = quadrics[edges[heap_top].m_verts[0]];
    LOD_NdQuadric & q1 = quadrics[edges[heap_top].m_verts[1]];

    const LOD_VertexInd v0ind = edges[heap_top].m_verts[0];
    const LOD_VertexInd v1ind = edges[heap_top].m_verts[1];

    LOD_Vertex &v0 = verts[v0ind];
    LOD_Vertex &v1 = verts[v1ind];

    LOD_NdQuadric sum = q0;
    sum += q1;


    if (m_collapser->CollapseEdge(
            heap_top,
            m_mesh,
            m_deg_edges,
            m_deg_faces,
            m_deg_vertices,
            m_new_edges,
            m_update_faces,
            m_update_vertices
    )) {

        // assign new vertex position

        v0.pos = new_vertex;
        v1.pos = new_vertex;

        // assign the new vertex color
            
        m_color_editor.SetColor(new_color,v0ind);
        m_color_editor.SetColor(new_color,v1ind);

        // sum the quadrics of v0 and v1
        q0 = sum;
        q1 = sum;

        // ok update the primitive properties

        m_face_editor.Update(m_update_faces);   
        m_face_editor.UpdateVertexNormals(m_update_vertices);

        // update the external vertex buffer 
        m_extern_editor.CopyModifiedVerts(m_mesh,m_update_vertices);

        // update the external face buffer
        m_extern_editor.CopyModifiedFaces(m_mesh,m_update_faces);

        // update the edge heap
        UpdateHeap(m_deg_edges,m_new_edges);

        m_quadric_editor->Remove(m_deg_vertices);
        m_face_editor.Remove(m_deg_faces);
        m_face_editor.RemoveVertexNormals(m_deg_vertices);      
        m_color_editor.RemoveVertexColors(m_deg_vertices);
                
        // delete the primitives

        DeletePrimitives(m_deg_edges,m_deg_faces,m_deg_vertices);

    } else {
        // the edge could not be collapsed at the moment - so
        // we adjust it's priority and add it back to the heap.
        m_heap->Remove(edges.begin(),0);
        edges[heap_top].HeapKey() = - MT_INFINITY;
        m_heap->Insert(edges.begin(),heap_top);
    }

    //clear all the temporary buffers

    m_deg_faces.clear();
    m_deg_edges.clear();
    m_deg_vertices.clear();
    
    m_update_faces.clear();
    m_update_vertices.clear();
    m_new_edges.clear();

    return true;

}   

    void
LOD_NdQSDecimator::
DeletePrimitives(
    const vector<LOD_EdgeInd> & degenerate_edges,
    const vector<LOD_FaceInd> & degenerate_faces,
    const vector<LOD_VertexInd> & degenerate_vertices
) {

    // assumes that the 3 vectors are sorted in descending order.

    // Delete Degnerate primitives


    // delete the old edges - we have to be very careful here
    // mesh.delete() swaps edges to be deleted with the last edge in 
    // the edge buffer. However the next edge to be deleted may have
    // been the last edge in the buffer!

    // One way to solve this is to sort degenerate_edges in descending order.
    // And then delete them in that order.
    
    // it is also vital that degenerate_edges contains no duplicates

    vector<LOD_EdgeInd>::const_iterator edge_it = degenerate_edges.begin();
    vector<LOD_EdgeInd>::const_iterator edge_end = degenerate_edges.end();

    for (; edge_it != edge_end; ++edge_it) {
        m_mesh.DeleteEdge(*edge_it,m_heap);
    }



    vector<LOD_FaceInd>::const_iterator face_it = degenerate_faces.begin();
    vector<LOD_FaceInd>::const_iterator face_end = degenerate_faces.end();
    
    for (;face_it != face_end; ++face_it) {
        m_mesh.DeleteFace(m_extern_editor,*face_it);
    }

    vector<LOD_VertexInd>::const_iterator vertex_it = degenerate_vertices.begin();
    vector<LOD_VertexInd>::const_iterator vertex_end = degenerate_vertices.end();
    
    for (;vertex_it != vertex_end; ++vertex_it) {
        m_mesh.DeleteVertex(m_extern_editor,*vertex_it);
    }
}


    bool
LOD_NdQSDecimator::
BuildHeap(
){
    // build the geometric quadrics 

    if (m_quadric_editor->BuildQuadrics(m_face_editor,true) == false) return false;

    // add in the property quadrics.
    ComputePropertyQuadrics();

    m_quadric_editor->InitializeHeapKeys(m_color_editor);

    m_heap = Heap<LOD_Edge>::New();
    // load in edge pointers to the heap

    vector<LOD_Edge> & edge_set= m_mesh.EdgeSet();
    vector<LOD_Edge>::const_iterator edge_end = edge_set.end();
    vector<LOD_Edge>::iterator edge_start = edge_set.begin();

    vector<int> & heap_vector = m_heap->HeapVector();

    for (int i = 0; i < edge_set.size(); ++i) {
        edge_set[i].HeapPos() = i;
        heap_vector.push_back(i);
    }
    
    m_heap->MakeHeap(edge_set.begin());

    return true;
}

    void
LOD_NdQSDecimator::
UpdateHeap(
    vector<LOD_EdgeInd> &deg_edges,
    vector<LOD_EdgeInd> &new_edges
){
    // first of all compute values for the new edges 
    // and bung them on the heap.

    vector<LOD_Edge>  & edge_set= m_mesh.EdgeSet();

    vector<LOD_EdgeInd>::const_iterator edge_it = new_edges.begin();
    vector<LOD_EdgeInd>::const_iterator end_it = new_edges.end();


    // insert all the new edges     

    // compute edge costs ffor the new edges

    m_quadric_editor->ComputeEdgeCosts(new_edges,m_color_editor);

    // inser the new elements into the heap

    for (; edge_it != end_it; ++edge_it) {      
        m_heap->Insert(edge_set.begin(),*edge_it);
    }


    // remove all the old values from the heap

    edge_it = deg_edges.begin();
    end_it = deg_edges.end();

    for (; edge_it != end_it; ++edge_it) {
        LOD_Edge &e = edge_set[*edge_it];
        m_heap->Remove(edge_set.begin(),e.HeapPos());

        e.HeapPos() = 0xffffffff;

    }
}
    
    void
LOD_NdQSDecimator::
ComputePropertyQuadrics(
){

    vector<LOD_TriFace> & faces = m_mesh.FaceSet();
    vector<LOD_Vertex> & verts = m_mesh.VertexSet();
    vector<LOD_NdQuadric> & quadrics = m_quadric_editor->Quadrics();
    const vector<MT_Vector3> &face_normals = m_face_editor.Normals();

    // compute the linear functionals for each face

    // For each property associated with that face we compute
    // a property gradient, construct a quadric based on this and add
    // it to each of the face's vertex quadrics.

    vector<LOD_TriFace>::const_iterator f_start = faces.begin();
    vector<LOD_TriFace>::const_iterator f_end = faces.end();
    vector<LOD_TriFace>::iterator f = faces.begin();

    // we need a little matrix space to help us with the
    // linear functional computation.

    TNT::Matrix<MT_Scalar> mat(4,4,MT_Scalar(0));
    TNT::Vector<MT_Scalar> vec(4,MT_Scalar(1));

    // some pivots.

    TNT::Vector<TNT::Subscript> pivots(4,int(0));

    // Quadrics now consume heap memory so let's
    // reuse one in the following loop rather than 
    // making one each iteration.

    LOD_NdQuadric qp;


    for (;f != f_end; ++f) {
        
        // collect the coordinates of the face
        // and the normal into a matrix
    
        const LOD_VertexInd * f_verts= f->m_verts;

        const MT_Vector3 & p0 = verts[f_verts[0]].pos;
        const MT_Vector3 & p1 = verts[f_verts[1]].pos;
        const MT_Vector3 & p2 = verts[f_verts[2]].pos;
    
        const MT_Vector3 c0 = m_color_editor.IndexColor(f_verts[0]);
        const MT_Vector3 c1 = m_color_editor.IndexColor(f_verts[1]);
        const MT_Vector3 c2 = m_color_editor.IndexColor(f_verts[2]);

        // get the face normal  

        const MT_Vector3 & fn = face_normals[int(f - f_start)];

        // load into mat

        int i;
        for (i = 0; i < 3; i++) {
            mat[0][i] = p0[i];
            mat[1][i] = p1[i];
            mat[2][i] = p2[i];
            mat[3][i] = fn[i];
        }
        mat[0][3] = MT_Scalar(1);
        mat[1][3] = MT_Scalar(1);
        mat[2][3] = MT_Scalar(1);
        mat[3][3] = MT_Scalar(0);

        // Compute the pivots

        if (TNT::LU_factor(mat,pivots)) {
            // bad face!
            continue;
        }   

        // compute red linear functional

        vec[0] = c0[0];             
        vec[1] = c1[0];
        vec[2] = c2[0];
        vec[3] = MT_Scalar(0);

        TNT::LU_solve(mat,pivots,vec);

        // construct a quadric based on this functional

        qp = LOD_NdQuadric(
            MT_Vector3(vec[0],vec[1],vec[2]),
            vec[3],
            0
        );          
        // compute green functional

        vec[0] = c0[1];             
        vec[1] = c1[1];
        vec[2] = c2[1];
        vec[3] = MT_Scalar(0);

        TNT::LU_solve(mat,pivots,vec);

        // construct a quadric based on this functional

        qp += LOD_NdQuadric(
            MT_Vector3(vec[0],vec[1],vec[2]),
            vec[3],
            1
        );          
        
        // compute blue functional

        vec[0] = c0[2];             
        vec[1] = c1[2];
        vec[2] = c2[2];
        vec[3] = MT_Scalar(0);

        TNT::LU_solve(mat,pivots,vec);

        // construct a quadric based on this functional

        qp += LOD_NdQuadric(
            MT_Vector3(vec[0],vec[1],vec[2]),
            vec[3],
            2
        );          
    
        // add to the geometric quadrics of each of the 
        // vertices of f
        
        qp *= MT_Scalar(50);    


        quadrics[f_verts[0]] += qp;
        quadrics[f_verts[1]] += qp;
        quadrics[f_verts[2]] += qp;
    
        qp.Clear();

    }
}